login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A025028 Numbers whose least quadratic nonresidue (A020649) is 23. 10
10559, 15791, 21118, 31582, 50951, 53231, 53881, 88079, 88919, 92569, 97919, 101902, 102001, 106462, 107762, 123191, 128519, 130729, 138311, 142271, 144169, 158759, 166319, 166609, 167879, 173209, 174599, 176158, 176401, 177838, 185138 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Quadratic Nonresidue.

PROG

(PARI) residue(n, m)=local(r); r=0; for(i=1, floor(m/2), if(i^2%m==n, r=1)); r

isA025028(n)=local(a); a=1; forprime(p=2, 19, a=a && residue(p, n)); a=a && !residue(23, n); a \\ Michael B. Porter, Apr 30 2010

(PARI) is(n)=forprime(p=2, 23, if(!issquare(Mod(p, n)), return(p==23))); 0 \\ Charles R Greathouse IV, Jan 24 2020

CROSSREFS

Cf. A020649, A025020, A025021, A025022, A025023, A025024, A025025, A025026, A025027, A025029.

Sequence in context: A065319 A063060 A187727 * A063063 A183600 A302772

Adjacent sequences:  A025025 A025026 A025027 * A025029 A025030 A025031

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 25 12:00 EST 2021. Contains 341606 sequences. (Running on oeis4.)